The greenhouse effect diagram explains in a simple drawing how global warming is possible. The image below makes clear why we’re facing climate change events such as sea level rise, polar ice caps melt and lethal heat waves in some parts of the planet. See the image below.
Greenhouse effect diagram drawing – simple version
Here you can find the climate change image prepared by the Hourglass team, read the explanation below.
Greenhouse effect diagram explained
As you can see in this greenhouse effect diagram, the global warming process is very simple.
The solar radiation reaches planet Earth (as in the orange arrows) but, thanks to the ozone layer, not all the radiation gets to our atmosphere.
Part of this UV rays are reflected back to space, defending our planet of the desctructive solar full strenght (what would make life on Earth simply impossible).
This low percentage of the sun radiation reachs the Earth surface, that gives it back to atmosphere.
As the ozone layer is (fortunately) there, just a part of this heat manage to escape back to space, represented by the green arrows. Part of it is hold in our planet atmosphere.
That’s also good news. If the heat could fully run out to the vacuum, the temperature on Earth would be so cold at night that would be just impossible to live here.
What’s the problem then? Climate change problem is related to greenhouse gases. Below, you can understand how this greenhouse effect causes global warming (due to man actions) and what is the greenhouse gases role in this cycle.
Greenhouse effect and global warming
Although natural, the greenhouse effect is not an immutable phenomenon, and changes in the chemical composition of the atmosphere imply changes in it. CO2, for example, is a very important greenhouse gas for us to understand the planet’s climatic history.
Studies using cylinders of ice from Antarctica prove the linear relationship between the planet’s average temperature and CO2 levels: the higher the concentration of this gas, the higher the temperature, and vice versa. Its levels, over the years, alternate between maximum (interglacial period) and minimum (glacial period), the so-called Milankovitch cycles.
However, CO2 levels had never exceeded the 300 ppm concentration in the atmosphere, until, with the intensification of human activities post-Industrial Revolution, we currently have a concentration of about 418 ppm, the highest level ever measured.
CO2, for example, is a non-condensable gas, which allows it to persist for a long time in the atmosphere. As the temperature rises, caused by the increase in carbon dioxide, the levels of water vapor present in the atmosphere increase.
It is quite true that water vapor is condensable, and its concentration is a consequence of the average temperature of our planet (and not the other way around).
When the water vapor levels reach the limit, it condenses, forms clouds, and then rain occurs. With the atmosphere supporting higher levels of water vapor, the greenhouse effect is further intensified, and a further increase in temperature occurs.
There is consensus in the scientific community that post-Industrial Revolution human activities have significantly altered the chemical composition of the atmosphere, especially the concentration of GHGs.
Since the second half of the twentieth century, meteorological and satellite data indicate that there is indeed an increase in global temperature, which has grown by more than 1°C since the pre-industrial period.
Global warming is actually a response by the planet. It is the Earth’s way of reestablishing the energy balance.
It should be pointed out that global warming is not related to an increase in solar radiation, because since 1980 it has been noticed that radiation levels have remained practically constant.
Nor is it possible to blame the warming on the Milankovitch cycles, because there is, by orbital theory, no warming trend on our planet predicted for the next few thousand years. Volcanic activity, on the other hand, does not act to warm the planet; on the contrary, the emission of particles reflects sunlight.
These are just a few reasons to exemplify why global warming is tied to increasing levels of GHGs in the atmosphere.
Greenhouse effect gases
“Several are the gases that can cause the greenhouse effect, however, among the main ones there are:
Carbon dioxide (CO2)
It is responsible for about 60% of the greenhouse effect, and can persist in the atmosphere for up to 1000 years.
It comes from burning, deforestation, and the burning of fossil fuels (such as diesel, gasoline, aviation kerosene, natural gas, coal, etc.). The loss of vegetation is impacting, because this is able to absorb CO2 from the air.
Methane (CH4)
The main component of natural gas is responsible for 15 to 20% of the greenhouse effect, and can remain in the atmosphere for up to a decade.
Oil and gas extraction, coal mining, and landfills account for 55% of anthropogenic methane emissions. A total of 32% of methane emissions can be attributed to ruminant animals, such as cows and sheep, which ferment food in their stomachs.
The decomposition of manure and the cultivation of rice are also agricultural activities that contribute to CH4 emissions. Methane is 80 times more potent than CO2 as a cause of global warming.
Nitrous oxide (N2O)
N2O s responsible for about 6% of the greenhouse effect, lasting for about 120 years in the earth’s atmosphere. Emissions from human practices are mainly attributed to agriculture.
Bacteria in soil and water already naturally convert nitrogen into nitrous oxide, but fertilizer use and runoff have added even more nitrogen into the environment.
Nitrous oxide is also present in emissions from the burning of fossil fuels. It is 280 times more potent than CO2 as a cause of global warming.
Chlorofluorocarbons (CFCs): responsible for up to 20% of the greenhouse effect, they are used in refrigerators, air conditioners, thermal insulation and foams and also as aerosol propellants.
Other GHGs are:
In addition, they can react with ozone in the stratosphere, thus creating the so-called hole in the ozone layer, a natural filter for harmful ultraviolet rays.
Although they can retain heat, this is offset by the stratospheric cooling that results from their ozone-destroying role.
Fluorinated gases: hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride. They are used as alternatives to CFCs, which are being phased out under the Montreal Protocol.
Although they are not very persistent and do not harm the ozone layer, fluorinated gases, in 20 years, may have a global warming potential 460 to 16,300 times greater than that of CO2.
Ozone (O3)
Contributes about 8% to the greenhouse effect. This gas is formed in the lower atmosphere, under the Sun’s stimulus, from nitrogen oxides and hydrocarbons from thermoelectric power plants, vehicles, and deforestation.
Water vapor (H2O)
This one is the most abundant GHG in the Earth’s atmosphere and is the largest overall contributor to the greenhouse effect.
However, almost all of the vapor present in the atmosphere is anthropically unrelated, being produced naturally. However, higher average temperature is thought to cause greater evaporation of water, thus increasing the vapor’s share of the greenhouse effect.
